In some color display systems, light from a white light source is separated into red, green, and blue. To achieve a desired color, red, green, and blue are projected at different times in the same location during a frame display time. The human eye perceives the desired color that is a mixture of the red, green and blue. The intensities of red, green, and blue can be adjusted to produce different colors.
FIG. 1 is an optical schematic diagram of a conventional color display system. Referring to FIG. 1, a lamp 100 projects white light through collimating optics 102 to a color wheel 104. Color wheel 104 typically includes separate sectors of red, green, and blue. Color wheel 104 may also include a white light sector. Light exiting color wheel 104 passes through beam shaping optics 106 and impacts a digital micromirror device (DMD) 108. DMD 108 includes individually controllable mirrors that reflect beams of red, green, and blue light through a projection lens 110 and onto a display surface 112.
FIG. 2 is a flow chart illustrating exemplary steps for displaying color images using a conventional display device, such as that illustrated in FIG. 1. Referring to FIG. 2, in step 200, projector hardware grabs a frame and selects a pixel to be displayed. In step 202, the hardware determines a desired pixel color. In step 204, the projector hardware selects intensities of red, green, and blue to achieve the desired pixel color. For example, if it is desired to display a dark green pixel, the intensity of red may be low, the intensity of green may be high, and the intensity of blue may also be high. In step 206, the projector displays red, green, and blue during a frame display time for a pixel to achieve the desired color. Displaying red, green, and blue with the selected intensities will cause the viewer to perceive the pixel as being dark green.
One problem with existing color projectors is that such devices utilize only 55% of the available color space. Using only red, green, and blue prevents the generation of many colors, such as those outside of the color triangle. In addition, true Pantone colors cannot be produced using only red, green, and blue.
Another problem with existing red, green, and blue projectors is that they are incapable of reproducing individual wavelengths or frequencies. For example, the red, green, and blue filters used by conventional projectors have wideband color bandwidths of approximately 100 or greater nanometers. For example, a green filter in a conventional color wheel may pass light in the green wavelength ranging from about 450 nanometers to 600 nanometers. Such devices are incapable of producing colors that contain only discrete, narrowband wavelengths or frequencies.
Accordingly, in light of these difficulties associated with conventional color projectors, there exists a need for improved methods, systems, and computer program products for full spectrum projection.